ServiceStack.Redis: "Unable to Connect: sPort: 0" and Unable to cast object of type 'System.Byte[]' to type 'System.Object[]'

Question

I have a test harness that repeatedly gets and sets DateTime objects so we can test fail-over of our new Redis Sentinel deployment.

I have added my license key to the static constructor of the calling class.

I have not made any client configuration so it should be using the defaults.

Gets and Sets succeed 99% of the time but I am getting intermittent failures like the ones below.

1. Unable to Connect: sPort: 0

   ServiceStack.Redis.RedisException: Unable to Connect: sPort: 0 at ServiceStack.Redis.RedisNativeClient.CreateConnectionError() at ServiceStack.Redis.RedisNativeClient.SendReceive[T](Byte[][] cmdWithBinaryArgs, Func1 fn, Action1 completePipelineFn, Boolean sendWithoutRead) at ServiceStack.Redis.RedisNativeClient.SendExpectMultiData(Byte[][] cmdWithBinaryArgs) at ServiceStack.Redis.RedisNativeClient.SentinelGetMasterAddrByName(String masterName) at ServiceStack.Redis.RedisSentinelWorker.GetMasterHost(String masterName)

   Other posts claim this could be related to the ConnectTimeout, but we are not setting it specifically and therefore the default (-1 / not set) should be being used. What is the issue?

2 . Unable to cast object of type 'System.Byte[]' to type 'System.Object[]'

2016-07-15 15:00:04,825 ERROR Caching.CacheCore.RedisCacheCore - Get<T> failed with key @#qm:qmth:testhardness-3be0f6bb-5df5-4205-afe4-45ee56b59a71
2016-07-15 15:00:04,825 ERROR Tools.RedisTestHarness.Program - READ - EXCEPTION [Duration: 00:00:00.4976532]: Unable to cast object of type 'System.Byte[]' to type 'System.Object[]'.
2016-07-15 15:00:04,825 DEBUG Tools.RedisTestHarness.Program -    at System.Linq.Enumerable.<CastIterator>d__1`1.MoveNext()
   at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at ServiceStack.Redis.RedisNativeClient.SentinelSlaves(String masterName)
   at ServiceStack.Redis.RedisSentinelWorker.GetSlaveHosts(String masterName)
   at ServiceStack.Redis.RedisSentinelWorker.GetSentinelInfo()
   at ServiceStack.Redis.RedisSentinel.GetSentinelInfo()
   at ServiceStack.Redis.RedisSentinel.GetRedisManager()
   at ServiceStack.Redis.RedisSentinel.GetValidSentinelWorker()
   at ServiceStack.Redis.RedisSentinel.Start()
   at Caching.CacheCore.RedisCacheCore.CreateManagerForSentinel(String connectionString, String sentinelHostFilter)
   at Caching.CacheCore.RedisCacheCore.CreateClientManager(String connectionString, Boolean useSentinel, String sentinelHostFilter)
   at Caching.CacheCore.RedisCacheCore.GetClient()
   at Caching.CacheCore.RedisCacheCore.Get[T](String key)
   at Caching.CacheCore.CacheCoreWrapper.<>c__DisplayClass1`1.<Get>b__0()
   at Caching.FunctionHandlers.ExecuteFunctionHandler.HandleFunction[T](Func`1 functionToHandle)
   at Caching.CacheCore.CacheCoreWrapper.Get[T](String key)
   at Caching.Cache.Get[T](String key)
   at Tools.RedisTestHarness.Program.Main(String[] args) in ...\Tools.RedisTestHarness\Program.cs:line 123

This makes no sense to me. Any ideas?

Both of these issues are preventing us from deploying to production.

Thanks for your help in advance.